Abstract
Objectives
This study was conducted to evaluate the radiological and clinical results of platelet-rich plasma (PRP) therapy in degenerative meniscal lesions.
Methods
Seventy patients with pain and grade 2 degenerative meniscal lesions on MRI (Magnetic Resonance Imaging) were included in the study. All patients underwent Knee Injury and Osteoarthritis Score (KOOS), Tegner-Lysholm, International Knee Documentation Committee Score (IKDC), Visual Analog Scale (VAS) clinical scores, and MRI scans before and 6 months after the injection.
Results
There was a statistically significant increase in Tegner-Lysholm, KOOS, and IKDC scores after the procedure (p=0.001; p<0.01), and a statistically significant decrease in VAS score after the procedure (p=0.001; p<0.01). However, no statistically significant difference was observed in MRI parameters (p>0.05).
Conclusion
It has been shown that the use of intra-articular PRP in painful degenerative meniscal lesions improves knee functions and helps reduce pain. However, no significant difference was observed in MRI controls. The results of our study indicate that the use of intra-articular PRP injection in patients with grade 2 meniscus degeneration improves clinical scores but does not result in significant improvement in degeneration as measured by MRI.
Keywords: Meniscus degeneration, Meniscus tears, Non-operative, Platelet-rich plasma, PRP, Regenerative medicine
Meniscal pathologies are common and are associated with an increased risk of osteoarthritis with age.[1] Meniscal degeneration plays a significant role in knee pain. Meniscus tissue undergoes micro- and macro-scale degeneration with age, resulting in knee pain and dysfunction.[2] Non-surface, intrasubstance signal increases detected on Magnetic Resonance Imaging (MRI) are defined as grade 2 meniscus degeneration.[3]
These lesions are considered a preliminary stage of meniscus tears, and no consensus has been reached regarding their treatment.[4,5] Non-operative therapy, focused on pharmacologic treatment (analgesics and/or non-steroidal anti-inflammatory drugs) and physical therapy, may provide pain relief as well as improve the mechanical function of the knee joint; however, it does not allow the degenerative process to regress. In addition, relatively weak intrinsic vascularity, hypocellularity, inflammatory mediators, and the combination of various proteases in the synovial fluid environment, along with complex mechanical loads, are factors that limit the spontaneous healing of the meniscus. However, each of these areas also represents potential avenues that can be manipulated to improve meniscus healing.[2,6]
In recent years, there has been an increasing trend in the use of platelet-rich plasma (PRP) injections for musculoskeletal problems. Current literature has exhibited that PRP injections are relatively safe and can potentially accelerate or augment the soft tissue healing process.[7]
PRP contains growth factors that provide cell proliferation (platelet-derived growth factor [PDGF], transforming growth factor-β, vascular endothelial growth factor [VEGF], epidermal growth factor [EGF]), thus reducing the effect of catabolic mediators (interleukin-1β, and metalloproteinases) and enabling the proliferation and differentiation of mesenchymal stem cells. At the same time, mechanisms of action such as suppressing the release of some inflammatory cytokines (interleukin-1 and tumor necrosis factor-alpha) and increasing the level of some anti-inflammatory cytokines (such as interleukin 10) have been included in the literature. Considering these mechanisms of action, it is thought that PRP can delay wear as a regenerative treatment in degenerative meniscus lesions.[8,9]
Our hypothesis is that, in painful degenerative meniscal lesions, intra-articular PRP application will contribute to pain control and functional recovery, slow or stop the degenerative process in the meniscus, and prevent the formation of tears that may require future surgical intervention.
Methods
This retrospective study approval was obtained from Sisli Hamidiye Etfal Training and Research Hospital Ethics Board (08.08.2017 – No: 840). This study was conducted in accordance with the Declaration of Helsinki (Medical Research Involving Human Participants).
Inclusion criteria were: Patients aged between 35 and 60 years, knee pain > 3 months, presence of grade 2 meniscus degeneration on MRI, no signs of malalignment, and Kellgren-Lawrence grade 2 or higher arthrosis on X-ray images, pain in the medial knee joint space by palpation.
Exclusion criteria were: Kellgren & Lawrence (K&L) grade II to IV in the medial and/or lateral compartment, intra-articular knee injections < 1 year, history of previous knee surgery, varus/valgus deformity > 5 degrees, pregnancy or breastfeeding, rheumatologic diseases, regular analgesic use for another reason, the presence of other causes of knee pain (ligament damage, osteochondral damage, chondromalacia patella, etc.), poor general health, hematological disease that can lead to coagulation disorder, hemoglobin value < 11, platelet count < 150,000/mm, and history of steroid therapy.
No physical therapy was applied to the patients. For the first 48 hours after the injection, the patients were informed that nonsteroidal anti-inflammatory drugs (NSAIDs) could be used in case of pain at the injection site, but they should not use any medication in the following period.
Between January 2015 and December 2015, 73 knees of 73 patients admitted to our clinic with knee pain were included in the study based on the inclusion and exclusion criteria. Age, sex, complaints, smoking use, body mass index, history, physical examination findings, special scores (Visual Analog Scale [VAS], Knee Injury and Osteoarthritis Score [KOOS], Tegner-Lysholm, International Knee Documentation Committee Score [IKDC]) and radiological examinations of each patient were recorded in a special form. In their medical history, trauma, bone diseases, neurological diseases, and rheumatologic diseases such as knee pain were questioned. The selected patients were evaluated by face-to-face interviews and their information was filed. VAS, Tegner-Lysholm, IKDC, and KOOS scores were used in the evaluations, and the total scores in these parameters were recorded. Evaluations were made before treatment and at 6 months of treatment. In addition, control MRI was performed at 6 months. Before and after treatment MR imaging of all patients was performed with a standard knee coil on a 1.5 Tesla MRI device (Avanto, Siemens, Germany).
After the initial evaluation, 2 patients were discontinued from treatment, and 1 patient was excluded from the study due to knee surgery after a sports injury. The study was continued with 70 knees of 70 patients and finalized. KOOS, VAS, IKDC, and Tegner-Lysholm scores were performed before injection. The patients were injected three times at one-week intervals. Sterilization was achieved by using 10% polyvidone-iodine locally at the injection site. The injection was performed using a 22-G syringe with a standard approach to the medial knee space while the patient was in the sitting position. The patients were sent home after injection and instructed to limit the use of the knee for 24 hours. In case of any complications or adverse effects, telephone numbers were provided to the patients. All patients were called at the end of the first week and the first month, and their satisfaction and problems were asked. The patients were asked to come back for a follow-up visit at 6 months.
In order to obtain PRP, a Biotrend-branded multi-purpose biological cabinet (Beautycell Stem Cell Workstation) was used. Before the injection, a 5 cc PRP sample was sent to the microbiology laboratory, and the platelet count was performed by a qualified microbiologist, ensuring that the platelet count was > 1,000,000 platelets per ml. For radiological assessment, all patients underwent MRI of the affected knee before treatment and at 6 months post-treatment. MRI was performed using a 1.5 Tesla scanner (Siemens Avanto, Germany) with a knee coil. Standard knee MRI sequences were obtained, in particular, proton-density and T2-weighted images in sagittal and coronal planes were used to evaluate the meniscus. On the base MRI, the meniscal degeneration was identified as an intrameniscal signal, and the slice showing the largest extent of the lesion was determined. The maximal width in the horizontal plane and the maximal height in the vertical plane of the intrameniscal high signal area were measured in millimeters using electronic calipers on the PACS workstation. The product of width and height was calculated to estimate the two-dimensional area of the degenerative lesion on that slice (in mm2). The same measurement methodology was applied on the 6-month follow-up MRI at the corresponding slice to assess any change in size of the meniscal lesion. Each MRI was reviewed by the same musculoskeletal radiologist, who was blinded to the clinical outcomes. Any new pathology, such as a new tear, progression, or chondropathy, was noted. Patients who developed new meniscal tears or other injuries during the study were excluded from analysis (as occurred with one patient who had a trauma-related meniscal tear requiring surgery).
Statistical Analysis
NCSS (Number Cruncher Statistical System) 2007 (Kaysville, Utah, USA) was used for statistical analysis. Descriptive statistical methods (mean, standard deviation, median, frequency, ratio, minimum, maximum) were used to evaluate the study data. Mann-Whitney U test was used to compare quantitative data and to compare two groups of variables that did not show normal distribution. Kruskal-Wallis test was used for comparison of triple and higher groups that did not show normal distribution. Bonferroni-corrected Mann-Whitney U test was used to determine the group causing the difference. Wilcoxon Signed Ranks test was used for intragroup comparisons of variables that did not show normal distribution. Spearman correlation analysis was used to evaluate the relationships between variables. Significance was evaluated at p<0.05. P<0.01 was considered significant.
The strength of the study is 1-β (β=II-type error probability) is expressed as and in general research should have 80% power. In our study, the number of cases that would be included in the study to obtain 80% power at the level of α=0.05 was determined as 69 when calculating a total of 95 cases that were admitted to our clinic and met our criteria using a simple random sampling method. 70 of the patients called by phone received a return, and continuity was provided for the study.
Results
A total of 128 patients were screened from the hospital registration system. We excluded 27 patients with Kellgren & Lawrence (K&L) grade II to IV in the medial and/or lateral compartment, 10 patients with intra-articular knee injections <1 year, 8 patients with a history of previous knee surgery, varus/valgus deformity >5 degrees, pregnancy or breastfeeding, and 10 patients with rheumatological diseases. After the initial evaluation, 2 patients were discontinued from treatment and 1 patient was excluded from the study due to knee surgery after a sports injury. The study was continued with 70 knees of 70 patients and finalized.
Of the 70 cases, 68.6% (n=48) were female and 31.4% (n=22) were male. The ages of the participants ranged between 35 and 60, with a mean age of 47.46±8.87 years (Table 1).
Table 1.
Population Characteristics
| Min-Max (Median) | Avr±SD | |
|---|---|---|
| Age | 35–60 (47) | 47.46±8.87 |
| BMI (kg/m2) | 18.2–38.1 (26.1) | 27.50±5.38 |
| n | % | |
| Gender | ||
| Woman | 48 | 68,6 |
| Man | 22 | 31.4 |
| Smoking | ||
| No | 45 | 64.3 |
| Yes | 25 | 35.7 |
| Treated Knee | ||
| Right | 37 | 52.8 |
| Left | 33 | 47.2 |
| Satisfaction | ||
| Very Satisfied | 46 | 65.7 |
| Satisfied | 17 | 24.3 |
| Not Satisfied | 7 | 10.0 |
BMI: Body Mass Index; Avr: Average.
There was a statistically significant increase in Tegner-Lysholm, KOOS, and IKDC scores after the procedure (p=0.001; p<0.01), and a statistically significant decrease in VAS score after the procedure (p=0.001; p<0.01) (Table 2, Fig. 1, Fig. 2).
Table 2.
Evaluation of clinical findings before and after the procedure (6 months follow up)
| Before Procedure | After Procedure | Difference | cp | |
|---|---|---|---|---|
| Tegner Iysholm | ||||
| Min-Max (Median) | 12-71 (32) | 7-94 (72) | 37.49±19.37 | 0.001** |
| Avr±SD | 32.57±12.46 | 70.06±17.42 | ||
| KOOS | ||||
| Min-Max (Median) | 7-65 (22) | 6-100 (74) | 46.60±24.56 | 0.001** |
| Avr±SD | 24.29±10.75 | 70.90±21.23 | ||
| IKDC | ||||
| Min-Max (Median) | 6-70 (25) | 11-93.1 (69.5) | 40.72±26.65 | 0.001** |
| Avr±SD | 26.29±12.39 | 67.01±19.81 | ||
| VAS | ||||
| Min-Max (Median) | 5-10 (8) | 0-10 (2) | -5.19±2.67 | 0.001** |
| Avr±SD | 7.96±0.92 | 2.77±2.34 |
KOOS: Knee Injury and Osteoarthritis Outcome Score; IKDC: International Knee Documantation Committee; VAS: Visual Analog Scale; Avr: Average.
Figure 1.
Post-procedure controls showed significant improvement in functional scores.
Figure 2.
A significant decrease in visual analog scale(VAS) score was observed in post-procedure controls.
No statistically significant relationship was found between the age and gender of the patients and the differences in Tegner-Lysholm, KOOS, IKDC, and VAS scores after the procedure (p>0.05) (Table 3, Table 4). However, it was found that smoking had a negative effect on improvement in clinical scores (p<0.05) (Table 5).
Table 3.
The effect of age on clinical scores
| Age | ||
|---|---|---|
| r | p | |
| Tegner Lysholm Difference | 0.131 | 0.278 |
| KOOS Difference | 0.174 | 0.156 |
| IKDC Difference | 0.162 | 0.180 |
| VAS Difference | -0.189 | 0.117 |
r=Spearman’s Correlation Coefficient; KOOS: Knee Injury and Osteoarthritis Outcome Score; IKDC: International Knee Documantation Committee; VAS: Visual Analog Scale.
Table 4.
The effect of gender on clinical scores
| Tegner Lysholm Difference | Koos Difference | IKDC Difference | VAS Difference | |
|---|---|---|---|---|
| Woman (n=48) | ||||
| Min-Max(Median) | -73-19 (-34.5) | -86-30 (-48.5) | -83-40 (-38.5) | -3-9 (5) |
| Avr±SD | -35.85±19.78 | -45.46±25.38 | -38.47±28.81 | 5.15±2.77 |
| Man (n=22) | ||||
| Min-Max(Median) | -72-15 (-41) | -82-7 (-46,5) | -78.2-13 (-42.2) | -2-9 (5) |
| Avr±SD | -41.05±18.39 | -49.00±23.12 | -45.64±20.96 | 5.27±2.51 |
| p | a0.217 | a0.728 | a0.324 | a0.873 |
KOOS: Knee Injury and Osteoarthritis Outcome Score; IKDC: International Knee Documantation Committee; VAS: Visual Analog Scale; Avr: Average.
Table 5.
The effect of smoke using on clinical scores
| Tegner Lysholm Difference | Koos Difference | IKDC Difference | VAS Difference | |
|---|---|---|---|---|
| Non User (n=45) | ||||
| Min-Max(Median) | -73- -3 (-41) | -86- -8 (-51.5) | -83-40 (-45) | 2-9 (6) |
| Avr±SD | -42.02±16.35 | -52.25±21.73 | -45.99±25.15 | 5.89±2.19 |
| User (n=25) | ||||
| Min-Max(Median) | -64-19 (-34) | -74-30 (-39) | -74,8-36 (-35) | -3-9 (4) |
| Avr±SD | -29.32±21.93 | -36.25±26.47 | -31.25±27.14 | 3.92±3.03 |
| p | a0.042* | a0.023* | a0.022* | a0.008** |
KOOS: Knee Injury and Osteoarthritis Outcome Score; IKDC: International Knee Documantation Committee; VAS: Visual Analog Scale; Avr: Average.
The changes in sagittal and coronal area measurements on MRI after the procedure were not found to be statistically significant (p>0.05) (Table 6).
Table 6.
Evaluation of Sagittal Area and Coronal Area Measurements on MRI
| Before Procedure | After Procedure | Difference | Change (%) | cp | |
|---|---|---|---|---|---|
| Sagittal Area | |||||
| Min-Max (Median) | 1.84-56.92 (11.74) | 2.08-48.40 (13.42) | -1.29±7.31 | -67.07-534.03 (2.89) | 0.771 |
| Avr±SD | 19.02±14.16 | 17.73±11.70 | 8.14±72.21 | ||
| Coronal Area | |||||
| Min-Max (Median) | 1.93-54.99 (13.13) | 1.53-48.92 (12.98) | -1.03±8.12 | -84.36-270 (3.41) | 0.686 |
| Avr±SD | 17.73±13.35 | 16.70±11.84 | 3.30±43.90 |
c Wilcoxon Signed Ranks Test; Avr: Average.
Discussion
In line with our hypothesis, good clinical results and high patient satisfaction have been obtained with intra-articular PRP application in painful degenerative meniscal lesions. However, no regression in intra-meniscal degenerations was observed in the measurements made in control MRI examinations.
The function of the knee meniscus for force transmission, shock absorption, stability, and proprioception has long been known. In meniscal pathologies, these functions are lost.[9] Meniscal pathologies can be classified as acute or degenerative. Symptomatic degenerative meniscus pathologies cause discomfort for patients. In addition, close relationships have been found between degenerative meniscus and traumatic tears.[2,10] Meniscal lesions have been classified into three grades, with grade 2 meniscal lesions (intrasubstance lesions) being incomplete horizontal lesions without connection to the surface or the bed of the meniscus. However, they can be considered a pre-stage of meniscal rupture.[10–12] Our study was also performed with intrasubstance meniscal lesions not accompanied by rupture.
The treatment strategies for these lesions are still controversial. Conservative treatment is not fully satisfactory.[12] Recent studies have shown that arthroscopic partial meniscectomy should not be recommended as a first-line treatment for degenerative meniscal lesions.[13,14] Therefore, new treatment modalities are needed for grade 2 meniscus lesions, and these methods should focus on regeneration. PRP allows the injection of high concentrations of autologous growth factors and bioactive molecules in a minimally invasive and low-cost manner.[15] Blanke et al.[16] reported that percutaneous PRP injection may be a good treatment alternative for intrasubstance meniscus lesions and that this therapy has the ability to achieve pain relief and halt progression on MRI. In our study, patients with intra-articular PRP injection had decreased pain and satisfactory functional results. However, no statistically significant improvement was observed in control MRI.
There is still controversy in the literature about the frequency and scheme of intra-articular PRP injection, and there is no standard protocol. Görmeli et al.[17] showed better clinical results after multiple PRP injections in early-stage osteoarthritis. In our study, 3 doses of PRP injections were performed one week apart. Wei et al.[18] showed that PRP has a positive effect on meniscal cells. PRP can increase vascularization and cell proliferation with the growth factors it contains, thus contributing to meniscus healing. Similarly, Bhargava et al.[19] showed that some anabolic growth factors (fibroblast growth factor, bone morphogenic proteins, transforming growth factor-β1, insulin-like growth factor-I, vascular endothelial growth factor, and platelet-derived growth factor) may contribute to meniscus healing. PRP is an autologous source of these cytokines and can be a promising treatment for meniscus degenerations.
Negative effects of smoking on wound and tissue healing have been known for many years. One of the important findings of this study is that functional results in smoking patients are worse than in non-smokers. This result is consistent with previous studies. Furthermore, smoking may impair platelet function,[20–23] which may explain this result.
Özyalvaç et al.[24] reported that good functional outcomes and significant regression in degeneration on MRI were observed in their series of 15 patients in which they performed ultrasonography (USG)-guided percutaneous PRP injection. Although the clinical results were similar to our study, we did not find similar results in radiological follow-up.
Alessio-Mazzola et al.,[25] in their study in which they published the 1-year prospective results of PRP application in 69 degenerative meniscus patients, reported high patient satisfaction and significant improvement in clinical scores. The results of this short follow-up study are in line with our study.
PRP showed efficacy in early osteoarthritic knee pathology in recent studies.[26–28] Moreover, Englund et al.[29] reported that degenerative meniscus lesions were the first signal of osteoarthritis. In our study, even though patients with grade 2 or higher arthrosis according to Kellgren-Lawrence staging were not included in the evaluation, the patients included in the study should be considered as candidates for future osteoarthritis. The biggest limitation of our study is that it did not include a placebo group, which can have significant effects on knee injections.
Conclusion
It has been shown that the use of intra-articular PRP in painful degenerative meniscal lesions improves knee functions and helps reduce pain. However, no significant difference was observed in MRI controls. Our study has a follow-up period of 6 months, but studies with longer follow-up periods are needed to assess the long-term effects of PRP.
The results of our study indicate that the use of intra-articular PRP injection in patients with grade 2 meniscus degenerations, despite its positive effects on clinical scores, did not show significant improvement in degeneration as measured by MRI.
Footnotes
Please cite this article as “Atalay Y, Eren OT, Armagan R. Intra-Articular PRP for Grade 2 Degenerative Meniscus Lesions; Radiological and Clinical Outcomes. Med Bull Sisli Etfal Hosp 2025;59(4):469-475”.
Disclosures
Ethics Committee Approval
The study was approved by Sisli Hamidiye Etfal Training and Research Hospital Ethics Committee (No: 840, Date: 08.08.2017).
Conflict of Interest
The authors declare that there is no conflict of interest.
Financial Disclosure
The authors declared that this study has received no financial support or any funding.
Use of AI for Writing Assistance
No support was received from any artificial intelligence application in the study.
Authorship Contributions
Concept – Y.A., O.T.E., R.A.; Design – Y.A., O.T.E.; Supervision – Y.A., R.A.; Fundings – Y.A.; Materials – Y.A., O.T.E.; Data collection &/or processing – Y.A., O.T.E.; Analysis and/or interpretation – Y.A.; Literature search – Y.A., R.A.; Writing – Y.A.; Critical review – Y.A., O.T.E.
Peer-review
Externally peer-reviewed.
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